Is the nutrient taurine really a key to healthy aging?

Scientists have long been trying to discover whether the popular supplement taurine can slow aging.

Evidence had suggested that levels of the nutrient found in meat and shellfish declined after midlife in people, meaning that taurine might be considered a marker for healthy aging. A 2023 international study confirmed that taurine decreased with age and then showed that taurine supplements could slow the aging process in several species of animals.

Now, a new study published in Science on Thursday found that taurine levels did not decline with age but, rather, were unchanged throughout adult life or even increased in some older people.

The seeming contradiction suggests that taurine measurements wouldn’t be an indicator for longevity and raises questions about its use as an anti-aging supplement. After expecting to find that higher taurine levels in the blood protected against inflammation or some chronic diseases, the finding surprised even the authors of the new study.

“We did this study to confirm what the first had done,” co-author Dr. Luigi Ferrucci, scientific director at National Institute on Aging, said in a press briefing. “Our purpose was really not to find the exact same association, but to find a strengthening.”

When their study was finished, “there was a large discrepancy,” he said. “This discrepancy needs to be analyzed more in depth because that may reveal some important mechanism with aging.”

The new findings do not rule out the possibility that boosting taurine with supplements might improve health in some people.

Vijay Yadav, co-author of the earlier study and head of the Rutgers New Jersey Medical School Healthy Longevity Program, said the new data will be important to the understanding of how taurine affects the aging process because it shows that it matters where the underlying data was collected.

One of the biological databases that was analyzed for his study came from a very homogeneous group of people from Finland, whereas one of the major sources of data for the new study was residents of Baltimore where the population is very varied genetically, he said.

“This would suggest to me that different genetic backgrounds or populations have different taurine values and data from different races or ethnicities cannot be pooled to interpret results,” he said. “It just means we need to better define the variables, genetic background is certainly an important one.” Others could include whether an individual has fasted or recently eaten.

It may turn out to be similar to the situation when scientists were trying to understand the relationship between blood sugar and diabetes, Yadav said. Initially, for example, it wasn’t known that it made a difference if samples were collected from someone who was fasting or had already consumed a meal.

The human body can make small amounts of taurine, although people mostly get it from food. Shellfish, dark chicken and turkey meat contain the highest levels of taurine. Other meats have moderate amounts of taurine. Dairy products have small amounts of the amino acid.

To shed light on whether a taurine supplement improves health and delays biological aging, Yadav and his colleagues are currently running a double blind, randomized placebo controlled trial.

The two papers are a good example of how science can work, said Dr. Peter Abadir, a specialist in geriatrics and an associate professor of medicine at Johns Hopkins University. Although the findings are very different, “that doesn’t mean one is right and one is wrong,” he added.

“The message from both these papers is we need more studies,” said Abadir, who was not involved with either.